You need to increase the dissolution rate of a slightly water soluble drug in tablet form. Propose three different solutions to this problem and explain why each of your solutions will solve the problem. (note that making a prodrug is not an option).

Given a 0.1 M NH4Cl solution: a) Which is the pH of this solution? b) If 100 mL of 0.1 M HCl solution are added to 100 mL of the original solution, which is the pH? c) And if 100 mL of 0.1 M NH3 are added to 100 mL of the original solution? Data: kb(NH3 ) = 1.8 10^-5 .

Provide a practical application of gelling properties of polysaccharides used in medical and industrial setting, and describe the mechanism of gelling for the application mentioned using a diagram.

2 SO3 (g) → 2 SO2 (g) + O2 (g) A sample of 2.0 mole of SO3 (g) is placed into an evacuated 2.0 L container and heated to 700K. The reaction occurs and the concentration of SO3 (g) as a function of time is shown in the graph below. Sorry the graph will not copy but is shows that SO3 at equilibrium is 0.4 mol/L

a) Determine the equilibrium concentrations of

SO2 (g) and O2 (g)

b) Calculate the value of the Kc and Kp equilibriumconstants for the reaction

1. Which is more dangerous if you spill it on your hand a 0.025 M HBr solution (Ka = 1.3 x 10⁶ ) or 0.75 M HClO₂ solution (Ka = 1.2 x 10^-2 )? Evaluate the H₃O⁺

^2. For each pair below indicate which is stronger and support your answer with an explanation. a. Which is a stronger acid, H₂S or PH₃? b. Which is a stronger base CO₃^-2  or C₂H₅O^-  ?

When an energetic electron with the velocity of 1.00 x 106 m s-1 was collided with Rb atom (assume stationary), Rb- anion moves at 313 m s-1 and released 382.4 nm of visible light. Calculate the energy change during the formation of Rb- anion from Rb atom in kJ mol-1

What is the pH of 0.51 M diethylammonium bromide, (C₂H₅)₂NH₂Br.
The K_b of diethylamine, (C₂H₅)₂NH, is 6.9 x 10^-4.

For all cycles in this section, assume that you have exactly 1.000 moles of gas and that the cycle is run reversibly. The known state parameters for the cycle will be given as the reduced temperature T_r ≡ T /T_c and reduced pressure P_r ≡ P/P_c, where T_c and P_c are the critical temperature and pressure of assigned diatomic molecule (N₂). Assume the gas is a diatomic van der Waals gas.

1. You have a Carnot cycle that begins with an adiabatic expansion from an initial state defined by a temperature of T_r = 1.75 and a pressure of P_r = 2.00 to a pressure of P_r = 1.75. The system then undergoes an isothermal expansion to a pressure of P_r = 1.25, followed by an adiabatic compression and then an isothermal compression back to the initial state. Calculate w, q, ∆U, ∆S, ∆S_sur, ∆H, ∆A and ∆G for each step in the cycle and for the total cycle.

(entropy S, enthalpy H, Gibbs energy G, and Helmholtz energy A.)

suppose that you repeated PART B of the experiment using 1M HNO3(aq). How would you expect the △Hneut to compare with that for the neutralization of HCL? explain.

△H = Hfinal - Hinitial = qp = △E + P △V

PART B - Enthalpy of Neutralization of a Stong Acid

The heat of neutralization of a strong acid, hydrochloric acid, will be determined. The strong base is sodium hydroxide of a concentration slightly less than that of the acid.

Procedure

1.In a clean dry graduated cylinder, measure out exactly 50 mL of the NaOH solution and transfer completely to the clean dry calorimeter. Record this temperature and the concentration of the NaOH solution.

2.Meanwhile, rinse out the graduated cylinder with tap water, distilled water and a few mL of the HCl solution. Measure out 50 mL of the HCl solution. Allow it to stand until its temperature is constant and equal to room temperature. Record this temperature and the concentration of the acid solution.

3.Add the acid as quickly as possible to the calorimeter, counting the time from the addition of the first drop of acid. Note the time and temperature after the addition of the last drop, and at 15 sec intervals from then on for 4 minutes. Stir the contents of the calorimeter constantly.

4.Test the contents of the calorimeter with litmus paper. The solution should be slightly acidic(pH<7.0), indicating that the known amount of base was completely consumed in the neutralization

If you use a strong base in high concentration to run the benzoin condensation, you will probably find that the product is not benzoin, but rather benzoic acid and benzyl alcohol. What has happened is that the Cannizzaro reaction has occured. How is this similar to the benzoin condensation? (research the mechanism and note what is similar/different)

65. Because carbon and silicon are both elements in group 14 on the periodic table, we expect them to react with other elements in similar ways. To some extent, then do, but in some cases, carbon and silicon compounds that seem to have analogous structures have very different chemical characteristics. For example, carbon tetrachloride, CCl₄ is very stable in the presence of water, but silicon tetrachloride, CCl₄, reacts quickly with water. The unbalanced equation for this reaction is

                SiCl₄ + H₂O à Si(OH)₄ + HCl

1. Balance this equation.
2. Write a conversion factor that could be used to convert between moles of SiCl₄ and moles of H₂O
3. How many moles of SiCl₄ react with 24 moles of water?
4. Write a conversion factor that could be used to convert between moles of Si(OH)₄ and moles of water.
5. How many moles of Si(OH)₄ form when 4.01 moles of H₂O react with an excess of SiCl₄?

"Starting with a 1.35 M HCl stock solution, five standard solutions are prepared by sequentially diluting 5.00 mL of each solution to 100.0 mL. What is the concentration of the final solution?"